1. Field of the Invention
The present invention relates to an optical disk device which is mounted on an electronic machine such as a personal computer, a notebook computer, a mobile terminal apparatus, or the like, and an optical pickup device which is suitably used in the optical disk device.
2. Description of the Related Art
An optical pickup device according to the related art will be described with reference to the accompanying drawings. FIG. 9 is a schematic view illustrating the construction of an optical system of the optical pickup device according to the related art. For the sake of simplicity, one light source is set, and the construction of an optical system for generating an RF signal, a tracking error signal, a focus error signal, and the like is omitted.
A laser light source 101 is a semiconductor laser diode which emits laser light for recording or reproducing information for DVD or CD. As the laser light source 101, a dual wavelength semiconductor laser light source may be set, in which light sources for a DVD or CD are installed adjacent to each other.
The light (hereinafter, referred to as emission light) emitted from the laser light source 101 is incident on a beam splitter 102. The beam splitter 102 is a prism having a polarization separation film as an inclined surface thereof. The beam splitter 102 separates the emission light into two separate directions, light is directed to an optical disk 107 and light is directed to a light amount monitor 109. This is to control the light amount of the laser light source 101. Further, the beam splitter 102 separates the emission light and incident light so that the light (hereinafter, referred to as incident light) reflected by the optical disk 107 is not returned to the laser light source 101 but is directed to an optical receiver 108.
The emission light directed to the optical disk 107 is incident on a collimator lens 103. The collimator lens 103 has a function of converting the emission light as divergent light into parallel light or converting the incident light as parallel light into converging light. The collimator lens is manufactured of optical glass or optical plastic.
The emission light converted into the parallel light by the collimator lens 103 is further reflected by an erect mirror 104 so as to be incident on a quarter wavelength plate 105. The erect mirror 104 is a mirror which vertically erects the light path which has been substantially parallel to the surface of the optical disk 107. The quarter wavelength plate 105 is manufactured of a birefringent optical material such as crystal so that the emission light, that is, the straight polarized light is converted into circular polarized light, and the incident light, that is, the circular polarized light is converted into straight polarized light perpendicular to the emission light.
The emission light passing through the quarter wavelength plate 105 is converted into the converging light by the object lens 106 so as to be focused on the optical disk 107. The object lens 106 is manufactured of optical glass or optical plastic. The optical disk 107 is one of various disks of a DVD and a CD.
The light reflected by the optical disk 107 passes through the object lens 106, the quarter wavelength plate 105, the erect lens 104, and the collimator lens 103 so as to be incident on the beam splitter 102. The incident light is separated from the emission light by the beam splitter 102 so as to be incident on the optical receiver 108. The optical receiver 108 receives the incident light so as to output an electrical signal which generates an RF signal, a tracking error signal, a focus error signal, or the like.
On the other hand, some of the emission light separated by the beam splitter 102 is incident on the light amount monitor 109. The light amount monitor 109 outputs an electrical signal corresponding to the amount of received light. A light amount control circuit 110 is present in an optical disk device main body (not shown). Based on the electrical signal output by the light amount monitor 109, the light amount control circuit 110 controls a power supply 111 for driving a laser light source so that the output of the light amount monitor 109, that is, the amount of light incident on the optical disk 107 becomes constant. The power source 111 causes the laser light source 101 to emit light with a predetermined output.
FIG. 10 is a perspective view illustrating an external appearance of the optical pickup device according to the related art. The above-described members of the optical pickup device are provided on the carriage 112 directly or through another member. In particular, parts as the laser light source 101 and the power source 111 for driving a laser light source, which are energized so as to be used, are mounted on a flexible printed circuit board 116 (hereinafter, referred to as an FPC) and are then mounted on the carriage 112. On the surface opposite to the optical disk 107, an upper surface cover 113 and an actuator cover 114 are installed so that the FPC 116 and the parts mounted on the FPC 116 do not come in contact with the optical disk 107. Therefore, only the parts such as the object lens 106, the actuator 115 for driving the object lens 106, a portion of the laser light source 101, and the like are exposed on the side opposite to the optical disk 107 of the optical pickup device.
However, when recording is performed on the optical disk 107, the high-power laser light source 101 and power supply 111 for driving a laser light source are needed. The laser light source 101 and the power supply 111 for driving a laser light source are heating elements. The more high-power the heating elements, the larger the heating value thereof. When the temperature of the heating element itself rises and exceeds the compensation temperature, a recording/reproduction characteristic can be affected by the rising temperature. In particular, due to the output of the laser light source 101, which is required for recording information at a high multiple speed, needing to be increased, a heating problem becomes prominent. In particular, since the power source 111 is disposed inside the optical pickup main body at the lower surface of the upper surface cover 113, heat is easily filled therein. Further, as the optical device is formed in a slim and compact shape, the optical pickup device is also required to be slim and compact. For this reason, the heating capacity reduces, and the temperature of the heating element is prone to decrease.
Thus, it is important that which method is used to suppress the increase of the temperature of the heating element of the optical pickup device. A technique in which the flow of air is used to discharge the heat generated by the optical pickup device is disclosed in P JP-A-10-124917, JP-A-2001-76362, and JP-A-2002-184167. In JP-A-10-124917, JP-A-2001-76362, there is a newly provided wind guiding member which guides the wind generated by the rotation of the optical disk 107 to a portion which should be cooled. Further, in JP-A-2002-184167, there is a newly provided air blowing section which sucks the air inside or outside the optical disk device so as to blow the air to a portion inside the optical disk device which should be cooled.
However, such techniques have not taken into account that the temperature of the heating element is kept low in a small-sized optical disk device and optical pickup device. By adding a new member, heat is radiated from an optical pickup device. Therefore, it is difficult to mount the optical pickup device on a small-sized optical disk device, and to ensure sufficient heat radiation properties though it can be mounted thereon.